The invention described herein relates generally to thermal protection structures for downhole tools and more particularly to an improved thermal protection apparatus for downhole electronics used in making geotechnical measurements.
Existing devices for controlling the temperature of heat-sensitive components in downhole applications in geothermal work utilize conduction and natural convection to transfer heat from an electronics compartment to a heat sink. Typically the only high conductivity paths directly connected to the heat sink are conventional brass rods and a copper bulkhead. A commonly used heat sink is Wood's metal, a bismuth lead alloy. It is desirable to construct a thermal protection apparatus which will protect heat-sensitive electronic components in geothermal environments for periods of time longer than those achieved by conventional devices.